Method and apparatus for controlling the metacentric height of ships



Aug- 19, 1941- H. F. NORTON TAL 2,253,246

METHOD AND APPARATUS FOR CONTROLLING THE METACENTRIC HEIGHT 0F SHIPSFiled Oct. l0, 1939 4 Sheets-Sheet L M ATToRfE 2,253,246 l METHOD ANDAPARA'IUS FOR CONTROLLING TvHEMETACENTRIC HEIGHT OF SHIPS AugT 19, 1941.H. F. NORTON ETAL 4 Sheets-Sheet 2 Filed Oct. 10, 41939 Aug. 19, 1941.v2,253,246 l METHOD AND APPARATUS FOR CONTROLLING THE METACENTRIC HEIGHTOF SHIPS y H. F. NORTON ETAL 4 Smets-sheet 3 Filed Oct. lO, 1959 Aug.19,`1941 'H F NORTON ETAL 2,253,246

METHOD AND APPARATUS FOR CONTROLLING THE METCENIRIG HEIGHT SHIPS Filed001'.. l0, 1939 4 Sheets-Sheel'l 4 Ka/ATTORNE Patented Aug. 19, 1941METHOD AND APPARATUS FOR CONTROL- `LING THE METACENTRIC HEIGHT OF SHIPSHarold F. Norton, Newport News, Va., and

Hiester J. Welch, Cavite, P. I.

"Application October 10, 1939, Serial No. 298,754

11 Claims.

The invention relates to a method and means for controlling themetacentric height of ships at sea.

The fuel oil and fresh Water supplies of passenger vessels are usuallycarried in double bottom compartments, and when these compartments arefull, the stability of the ship is increased by reason of the increasein the metacentric height which is produced by the addi- -tional Weightof the fuel and water in the bottom of the vessel. As the vesselproceeds on a voyage, this fuel oil and fresh water are gradually useduntil toward the end of the voyage a considerable number of the innerbottom tanks have been emptied and the stability of the vesselcorrespondingly reduced.

The present Government 'regulations require that a certain standard ofstability be maintained throughout the entire voyage. In order to complywith these regulations it becomes necessary in accordance with presentmethods and equipment, for the master of the vessel to see that some orall of the inner bottom tanks are refilled with salt Water ballast asthey become empty. This involves pumping the salt Water out of the tankswhen the end of the voyage is reached,and thoroughly cleaning the tanksbefore they can be relled with fuel oil or fresh Waterfor the nextvoyage. This entails'considerable expense and: the Vpresence of the saltWater in the tanks increases corrosion and consequently adds tomaintenance costs.

It is an` object of the present invention to provide method` and meansfor controlling the stability of ships through regulation of themetacentric height with Water ballast, yet which in normal operationovercomes the difficulties mentioned above. Y l

A` more: particular object is to` provide method and means forregulating the metacentric height of vessels VWhile in transit in such aWay as 'to produce,` improved `riding characteristics under safe sailingconditionsfwhile'providing for a rapid increase inthev metacentricheight against the possibility of encountering hazardous sailingconditions.

A further object of our invention is to provide an emergency Water:ballast system which makes it possible normally to operate the shipWithout admitting Water ballast to the empty inner bottom fuel and/orfresh water compartments. l

A further specific `object is to` provide an emergency control foru themetacentric height which can be operatedyfrom the bridge by a commoncontrol Which by preselection admits water rapidly to the empty innerbottom fuel and/or Water tanks and/or tanks for other liquid supplies.

A further object is to provide emergency apparatus of the characterdescribed which is simple and inexpensive to construct and which doesnot require the use of extensive piping for admitting` the Water ballastto the preselected empty tanks.

`It is also an object of our invention to provide a method and apparatusof the character described in Which the inner bottom tanks are arrangedfor emergency flooding with sea Water, but are effectively protectedagainst infiltration of sea Water sol long as they contain other liquidsor are being maintained empty. l

Other objects and advantages Will appear a the description proceeds.

In accordance with our invention, openings are provided in the hull foradmission of Water ballast to the inner Vbottom tanks, theseopeningsnormally being closed. The individual tanks are emptied asneeded during transit, each tank being connected to a common floodingcontrol as it becomes empty. These tanks are kept empty to maintain alow metacentric height during safe sailing conditions, but whenhazardous sailing conditions are encountered `the common ooding control`is operated to flood some or all ofthe empty tanks simultaneously byadmitting Wat-er through the hull openings to quickly increase themetacentric height. In accordance Withl our preferred system, theflooding control is operated from the bridge, and the flooding can bestarted instantaneously Without recourse to the controls for theindividual tanks. The individual selective controls may also be used toadmit sea Waterif necessary, to tanks that are only partially emptied offuel oil or fresh Water.

An important feature of our invention resides in maintaining, duringnormal or safe sailing Y conditions, the empty condition of the tanksfrom which fuel and/or fresh Water has been withdrawn. `This ordinarilyWill mean that the vessel Will; reach port Without the necessity of'admitting salt Water ballast to any of the empty inner bottom tanks.'I'his avoids the necessity of pumping ballast from the tanks andcleaning them preparatory' to taking on new supplies of fueloilandfreshwater; yet this is accomplishedv Without increasing the Ysailing hazardsby reason of the possibility of quickly increasing the metacentrioheight ofthe ship by admitting Water :ballast to some or all of theempty tanks simultaneously in the event .that this should becomenecessary in order to achieve the desired stability upon encounteringhazardous sailing conditions. Moreover, the additional fuel which wouldhave been required to carry the salt water ballast Will `have beensaved. Also, by our invention, safe operation of the ship is madepossible at a small metacentric height. This results in easy motion atsea, which contributes to the comfort of the passengers.

Another important feature of the invention resides in the provision of aspecial cofferdam or valve chamber which is so constructed as to permitaccess to the valve for inspection and repair and also to permitWithdrawal of such water as may seep in through the sea valves, thuseffectively preventing any infiltration of such Water through thecofferdam valves leading to the tanks.

A still further feature of the invention resides in the arrangement ofthe sea valves and cofferdams in such a way as to admit water throughthe hull directly into each of the tanks whereby extensive piping isavoided, while at the same time permitting the tanks to be flooded withmaximum speed.

These and other features of the invention will be explained more fullyin the description which follows.

In the drawings We have shown a preferred embodiment of apparatusconstructed in accordance with our invention as applied to passengerships for operation in accordance with our novel method.

Fig. 1 is an inboard profile, or diagrammatic vertical sectional view,of a ships hull embodying apparatus operable in accordance with theinvention; and Fig. 2 is a diagrammatic plan view of the double bottomcompartments of the same hull.

Figs. 3, 4, and 6 are detail sectional views of a preferred form ofcofferdam and valve construction applicable to the hull shown in Figs. land 2. Fig. 3 is a vertical transverse sectional view through thecofferdam and sea valve; Fig. 4 a horizontal sectional View showing thevalve layout; and Figs. 5 and 6 enlarged vertical sectional views on thelines 5--5 and 5 6 respectively of Fig. 4.

Referring to Figs. 1 and 2, we have shown a double-bottom hull havinginner bottom tanks or compartments I and 2 formed between the bottoms 3and il, transverse partitions or bulkheads 5 and longitudinal walls 6.Some or all of the compartments I and 2 normally carry liquid suppliesintended for consumption at sea. Thus the tanks A may be considered tonormally carry fuel oil, and the tanks B to normally carry fresh Water.The group of tanks C, comprising all of the tanks A and some of thetanks B, as indicated in Fig. 2, are considered to be designed to holdsufficient salt water ballast to provide stability for the oodability indamaged condition required by the Government regulations applying to theship. lThe tanks D, the fore peak 'I and the after peak 8 may be used inthe usual way to carry fresh water or fuel oil or salt water ballast, asmay be desirable in connection with the operation of the ship. As shownin Figures l and 2 our invention is practiced only in connection withtanks comprised in group C, but it is to be understood that it can bemade to apply to whatever group of tanks best suits the operatingconditions of the ship and that accomplishes the purpose of providingthe necessary stability for the compartment oodability required by theGovernment regulations applying to the ship.

In accordance with our invention, coiferdams are arranged at the sidesor corners of adjacent tanks so as to provide valve chambers 9 throughwhich each of the compartments in group C are connected to a sea valvein the bottom 3. Preferably the chambers 9 are so arranged that eachchamber affords a direct connection to three or four separatedouble-bottom compartments, as shown in Fig. 2.

Referring now to Figs. 3 to 6 inclusive we shall describe a coiferdamand valve arrangement which is particularly adapted to carrying out ourinvention. The valves shown are arranged for hydraulic operation but anyother suitable type of power actuated valves may be substitutedtherefor. The chamber 9 affords direct connection to four of thedouble-bottom compartments 2, being formed by the bottoms 3 and f3,bulkhead 5, transverse cofferdam wall I0 and longitudinal walls II. Thesea valve l2 comprises housings I3, I6, and I5, and a gate I6 connectedby a rod li' to a piston IB within the hydraulic cylinder I9. An inletstrainer 28 is provided at the entrance to the housing I d. The openingin the bottom 3 may be reinforced by a ring 2I, the edge of the openingbeing clamped between this ring and the flange 22 of the housing I4.

The piston I8 is double acting, the cylinder I9 being connected by thepipe-lines 23 and 24 to a suitable source of hydraulic power. A valve 25in the line 23 provides means for rendering the hydraulicgate-withdrawing means inoperative so long as the compartments adjacentchamber 9 contain fuel oil or othery liquid supplies.

Smaller valves 26 are arranged to control communication between thechamber 9 and the several compartments 2. These valves may be of thesame type as the valve I2, having gates 21 hydraulically actuated bydouble-acting pistons I8 operating in the cylinders 28. The cylinders 28are connected by pipe-lines 29 and 30 through a suitable controlmechanism to a source of hydraulic power.

A sounding tube SI extends into the chamber 9, preferably terminatingjust above the bottom 3 and providing means for detecting the presenceof water within the chamber 9. Another pipe 32, which also terminatesjust above the bottom 3, is connected to a bilge suction pump so that ifthere is any leakage into the chamber 9 when the valve I2 is closed, theseepage water can be evacuated, thus preventing it from reaching thelevel of the valves 26 and thereby insuring against any infiltration ofsea water into tanks which it is desired to maintain empty, or diffusionof sea water into tanks containing fuel or other liquid supplies. Amanhole 33 with a cover 34 provides access to the chamber 9 forcleaning, inspection and maintenance purposes.

It will be understood that each of the chambers 9 are provided with oneor more sea valves and one or more coiferdam valves leading to theadjacent double bottom compartment or compartments.

Each of the pipe-lines 29 of the cofferdam valves in the variouschambers 9 is provided with a suitable valve, such as the valve 25previously referred to in connection with the valve I2. This providesindependent control of the cofferdam gate valves 2E. Also each of thepipe-lines 29 and the pipe-lines 3B lead to a common control which ispreferably located on or near the bridge of the ship. Such a common`control is shown at 35 in Fig. `3,1and may consist of a three-Way orfour-way valve, or a Yseries of such valves, arranged on a common shaftor otherwise connec'ted to a single actuating means. From the control 35the pipe-line orlpipe-lines 36 llead to a hydraulic pump andthepipe-line or pipe-lines 31 lead to an overboard discharge or back to theintake side of the hydraulic pump.

The ship, when embarking `on a voyage, normally will have most of theinner bottom compartments 2 filled-with liquid supplies such as fuel oiland fresh water. In `accordance with our invention, the individualcompartments are emptied as needed during transit and as eachcompartment becomes 1empty, it is connected to the common iioodingcontrol 35 as by means of opening a valve (correspondingto the valve 25)in the pipe-line 29. If the valve 25 in the pipeline 23 leading into thepaticular chamber 9 which `provides communication with the compartmentthat is being cut in to the common control has not previously beenopened, it will be opened at this time to connect the valve l2 to thecommon control. For example, let us consider the four compartments 2a,2b, 2c and 2d adjacent the chamber 9 as shown in Fig. 4. At the start ofthe voyage, these four compartments will contain-let us say--fuel oil.Now consider that compartments 2a and 2c1 are connected to the burnersupply lines and become empty. The

`valves in the pipe-lines '29 associated with the gate valves 26 whichcontrol the opening between these particular compartmentsand the chamber9 are` now opened so as to connect these lines to the commonlioodingrlcontrol 35. The line 23 likewise is connected to this commoncontrol. It may also `be desirableto have valves in the `lines 24 and3!) in which case these valves are also regulated in the same manner asthe valves 25. The control will be in the position shown in fullline'sat 35, in which position the gates I6 and 2l will remain closed.Asother compartments become empty, they toovwillfbecut in to the comooncontrol butall of rthese compartments will be kept empty to maintain alow metacentric L height during safe sailing conditions. In the eventthat hazardous sailing conditions are en'- countered at any time duringthe voyage,`such as might be occasioned by damage to the ship or runninginto heavy seas, so i that it becomes necessary to havergreaterstability, the common control 35 is moved into position 35', connectingthe preselected lines 23 and 29 to the line or lines 36 leading to thehydraulic pressure source 38.

Jin

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instantaneously without recourse to the separate controls for theindividual tanks, whichv is of I great value in an emergency.

It will be understood that an electrical control system or any othersuitable type of submersible operating gear may be substituted for thehydraulic control which we have shown for purposes of illustration. Ifdesired, there may be duplicate controls on the bridge and in the engineroom, or at such other locations as may be deemed expedient. Ordinarilythe arrangements for ooding empty inner bottom tanks are such as topermit each tank to be flooded as it becomes empty, the sea water beingadmitted or pumped through long lengths of relatively small piping. Thismakes it necessary to pump the saltwater out of the tanks when the endof the voyage is reached and the tanks must be thoroughly cleaned beforethey can be relled with fuel oil or fresh water for the next voyage. Inaccordan-ce with our invention, however, it is normally possible tocomplete the voyage without admitting salt Water ballast to any of theempty tanks, except as may be necessary for other purposes such astrimming the ship. This also creates a saving of fuel inasmuch asV theadditional fuel which would have been required to carry the salt waterballast will have been saved. Moreover, the ship can be operated safelyat a small metacentric 4height which results in improved ridingcharacteristics under normal sailing conditions.

If desired or suitable to the arrangement of the vessel, the walls ofthe chambers 9 may be separated from those of the tanks, so long asdirect communication is maintained between the chambers and the adiacentinner bottom compartments whereby flooding can be performed quicklythrough large openings. The compartments 2 may and `in general will, beprovided with the usual venting arrangements to permit displacement o'fair therefrom when they are be-V ing filled with fuel oil orfresh water,orwhen they are being flooded* Inasmuch as such arrangements are wellknown in the art, it is not necessary to include a description of themhere.

The term "liquid supplies as used herein and in the appended claimsrefers to liquid consumable Astores such as fuel oil, fresh water andthe like, which are commonly carried in double bottom compartments andintended for 'consumption at sea. i

It will be understood that various modiiications canbe made in thearrangement which We have specifically described while retainingimportant advantages of the invention. The terms `and expressions whichwe `have employed are used as terms 'ofdescription and not oflimitation, `and we have no intention of excluding such equivalents ofthe `invention set forth, or of portions thereof, as fall within thepurview "of the claims. Y

We claim:

l. In apparatus for controlling the metacentric height olf ships, aplurality of closed tanks arranged in the ships bottom, chamberscommunicating directly with the tanks and also communicating directlywith openings in the ships p bottom, valves for controllingcommunication from the chambers to the tanks, valves for controllingcommunication from the chambers to the openings in the ships bottom, andmeans for withdrawing water from the chambers when the valves areclosed.

2. Inapparatus for controlling the metacentri-c height of ships, a tankarranged in the ships bottom, a sea valve in the ships bottom adjacentthe tank, a coiferdam between the tank and the sea valve, a valve in thecofferdam communieating directly with the tank at a point above thelevel of the sea valve, and means for withdrawing `water from the spacewhich separates the cofferdam valve and sea valve to prevent seepagewater from reaching the level ofthe cofferdam valve.

3. In apparatus for controlling the metacentric height of ships, fueltanks arranged in the ships bottom, sea valves in the ships bottomadjacent the tanks, cofferdams between the tanks and theV sea valves,valves in the cofferdams communioating directly with the tanks at pointsabove the levels of the adjacent sea valves, and means for withdrawingwater from the cofferdams to empty them after the valves have beenclosed following flooding of the cofferdams to iill empty fuel tanksWith water ballast.

4. In apparatus for controlling the metacentric height of ships havingliquid supplies tanks in the bottom, openings in the hull for admittingwater to such tanks, means for closing the hull openings, means forwithdrawing water seeping past the closing means to effectively seal thetanks against iniiltration when the tanks contain supplies and when theyare empty, means for emptying individual tanks as needed during transit,and means for ooding a plurality of such tanks simultaneously byadmitting water through the hull openings to quickly increase themetacentric height when hazardous sailing conditions are encountered.

5. Method of controlling the metacentric height of ships having liquidsupplies tanks in the bottom and openings in the hull for admittingwater to such tanks, which comprises closing the hull openings,withdrawing water seeping past the closed openings to effectively sealthe tanks against infiltration when the tanks contain supplies and whenthey are empty, emptying individual tanks as needed during transit,maintaining the sealed condition of the empty tanks during safe sailingconditions, and flooding a plurality of such empty tanks simultaneouslyby admitting water through the hull openings to quickly increase themetacentric height when hazardous sailing conditions are encountered.

6. Method of controlling the metacentric height of ships having liquidsupplies tanks in the bottom, which comprises the steps of emptyingindividual tanks as needed during transit, keeping such tanks empty tomaintain a low metacentric height during safe sailing conditions, andiiooding a plurality of such empty tanks simultaneously by admittingwater through the hull to quickly increase the metacentric height whenhazardous sailing conditions are encountered.

7. Method of controlling the metacentric height of ships having liquidsupplies tanks in the bottom, which comprises the steps of emptyingindividual tanks as needed during transit, keeping such tanks empty tomaintain a low metacentric height during safe sailing conditions, andooding a plurality of such empty tanks simultaneously by admitting waterdirectly through the bottom to quickly increase the meta.. centricheight when hazardous sailing conditions are encountered.

8. Method of controlling the metacentric height of ships having liquidsupplies tanks in the bottom, which comprises the steps of emptyingindividual tanks as needed during transit, keeping such tanks empty tomaintain a low metacentric height during safe sailing conditions, andflooding a plurality of such empty tanks simultaneously by admittingwater through the hull at points directly adjacent each empty tank toquickly increase the metacentric height when hazardous sailingconditions are encountered.

9. Method of controlling the metacentrio height of ships having liquidsupplies tanks in the bottom, which comprises the steps of emptyingindividual tanks as needed during transit, connecting each tank to acommon iiooding control as it becomes empty while keeping such tanksempty to maintain a low metacentrio height during safe sailingconditions, and operating the common ilooding control to flood aplurality of such empty tanks simultaneously by admitting water throughthe hull to quickly increase the metacentric height when hazardoussailing conditions are encountered.

l0. In apparatus for controlling the metacentric height of ships havinginner bottom tanks for liquid fuel, and chambers arranged between theshell and inner bottom in such a way that at least one chamber liesdirectly adjacent each tank which is to be used for auxiliary waterballast, each chamber having a valve controlling admission of water tothe chamber through the shell and a valve controlling admission of waterfrom the chamber to at least one of the tanks.

l1. In apparatus for controlling the metacentric height of ships havinginner bottom tanks for liquid fuel, chambers arranged between the shelland inner bottom in such a way that at least one chamber lies directlyadjacent each tank which is to be used for auxiliary water ballast, eachchamber having a valve controlling admission of water to the chamberthrough the shell and a valve controlling admission of water from thechamber to at least one of the tanks, a common control for the valves,and means for selectively connecting the valves to the common control toprovide for emergency ooding of the empty tanks simultaneously whilepreventing diffusion of water into the tanks containing fuel.

HAROLD F. NORTON. HIESTER J. WELCH.

` CERTIFICATE OE CORRECTION. Patent No. 2,255,2li6. August I9-, 19in.

HAROLD E, NORTON, ET AL.

It is hereby `certified that error eppe ars in the printed specification of the above nurnbered patent requiring oorrection as follows:Page 5, seolond column, line 50, beginningwith "l, In apparatus strikeout all to and .including the word and period. "closed." in line 60comprising claim l end fer the eleime new numbered 2, 5, LI, 5, 6, 7 8,9, IO and II reed I, 2, 5, LI, 5, 6, 7, 8, 9 end IO reepeetveiy; end metthe Seid Lettere Petlent should be read with this `correction thereinthat the same may conform to the recordA of the case in the PatentOffice.

Signed and sealed this 11th day of November, A. D. 1911.1.

Henry Van Arsdale,

(Seal) Y Acting Commissioner of Patents.

